The present invention relates to medical equipment, and, more particularly, to an apparatus for direct blood transfusion.
The apparatus of the present invention may be advantageously employed for direct blood transfusion as well as for introducing various medicamental liquids into the recipient's blood system.
There exist a variety of widely known apparatus for direct blood transfusion which usually comprise two needles coupled with tubes, one needle being introduced into the donor's blood system, while the other into the recipient's blood system, as well as a means for delivering blood from the donor to the recipient via said tubes. In order to prevent or combat blood clotting in the tubes, the latter must be regularly washed. To this end, the known apparatus are provided with a vessel (or several vessels) containing a medicamental liquid compatible with blood. The known apparatus also incorporate a distributing means, usually formed as a cock, which communicates with the above-described tubes as well as with the vessel containing the medicamental liquid. When the distributing means is set to one position, blood is delivered via the tubes from the donor to the recipient; with the distributing means set to the other position, said tubes undergo washing.
Blood is delivered from the donor to the recipient with the aid of a wide variety of pumps, such as centrifugal pumps, simplex, duplex and triplex pumps, reciprocating squirt pumps, plunger-type pumps, diaphragm pumps with a hydraulic drive, pumps with a monolithic compression plate, air-driven peristaltic pumps, gas-driven diaphragm pumps, pumps with a monolithic compression and flexible plate, etc.
From among the known apparatus for direct blood transfusion, the most popular variety uses the principle of continuous pumping of blood from the donor to the recipient, Beck's apparatus being the most widely known unit of this category.
This prior art apparatus comprises two needles coupled to rubber tubes. One needle is introduced into the blood system of the donor, the other into the blood system of the recipient. The above rubber tubes are interconnected by means of a glass tube affording a means of visual inspection of the transfusion process. The apparatus also incorporates a means for delivering blood from the donor to the recipient via the above-mentioned tubes, which means is formed as a drum with rollers disposed thereon.
In order to periodically wash the tubes with a view to preventing or combatting clotting therewithin, the apparatus is provided with a vessel containing a medicamental liquid compatible with blood. Additional tubes similar to the above-described ones have their free ends immersed in the vessel with the medicamental liquid, said additional tubes as well as the tubes connected to the needles which are introduced into the blood systems of the donor and the recipient being disposed on said drum.
The apparatus further comprises a distributing means in the form of a two-way cock communicating with said tubes as well as with the vessel for the medicamental liquid. The cock is mounted between the rubber tube connected to the needle introduced into the donor's blood system and one of the rubber tubes immersed in the vessel with the medicamental liquid.
With the cock set to one position, as the drum rotates, in one direction, the rollers run on the rubber tubes connected to the donor's and recipient's needles. Where the rollers come into contact with the tubes, the latter are deformed, so that the cross-section of the tubes alternately decreases and increases, causing blood to flow from the donor to the recipient through the tubes connected to the blood-collecting and infusion needles, and simultaneously causing the medicamental liquid to flow through the tubes having their free ends dipped in the vessel with the medicamental liquid. Thus blood transfusion via one set of tubes is accompanied by the washing of the other set of tubes.
In order to wash the tubes connected to the donor's and recipient's needles, they are replaced by the additional tubes. To this end, the recipient's needle is disconnected from the rubber tube which has been supporting blood flow and connected to the rubber tube earlier immersed at one end in the vessel with the medicamental liquid, and one end of the rubber tube disconnected from the recipient's needle is immersed in said vessel. The cock is set to the other position, ensuring communication of the tube connected to the blood-collecting needle with the tube newly connected to the recipient's needle. Then the direction of rotation of he drum is reversed, and the transfusion procedure carried out, with blood flowing through one set of tubes and the medicamental liquid through the other.
However, apparatus of the above-described type cannot be employed for direct blood transfusion what with the high risk of the donor being infected from the recipient carrying infectious diseases, purulent infection, septic, tuberculous and venerial diseases, malignant neoplasms and malignant blood disorders.
In the above-described apparatus, blood is delivered from the donor to the recipient as a result of mechanical effort exerted on the blood-carrying tubes or directly on the blood flux by the components of the blood-delivery means (pins, rollers, pistons, etc.), partially destroying the formed elements and plasma of the donor's blood, which detracts from the therapeutic potency of the blood, raises its coagulability and susceptibility to clotting.
Such a mechanical effort is likewise liable to damage the tubes wherethrough blood flows, necessitating their frequent replacement, which adversely affects the maintenance aspect.
The means for blood delivery employed in the prior art apparatus require electric motors, mechanical drives or manual efforts on the part of the operators.
Blood transfusion procedures with the use of the prior art apparatus must employ flow meters if the quantity of blood transfused is to be known.
The above two factors add to the design complexity of the apparatus, involve operational difficulties and raise the overall costs.
The prior art apparatus are not amenable to continuous operation, for they require frequent stoppages in order to wash the tubes through which blood flows from the donor to the recipient.
Blood transfusion with the use of the prior art apparatus can be handled by at least two operators, whereas the present invention requires only one person.
In particularly severe cases, prolonged infusion of medicamental liquids to the patients is required. But the prior art apparatus cannot be used for infusing a medicamental liquid prior to and immediately after direct blood transfusion avoiding all manipulations with the recipient's needle associated with the disconnection of the needle from the direct blood transfusion outfit and its connection to the vessel containing the medicamental liquid.